Double coils for PI

[HAPPY]

Double coils （up and down），not DD.Could you explain how it works in details,give me more information，Thank U.

[Carl-NC]

Not sure what you mean. Can you point to an example?

[HAPPY]

Just like Lorenz DEEPMAX Z1,the up coil shield interference from high-voltage lines，the down coil receive metal signals .it looks so interesting.

[6666]

• 14" (35cm) DD Search Coil
• 40" x 40" (1m x 1 m) Frame Search Coil

???????
From their site
The Lorenz Deepmax Z1 is a high quality specialist detector and it is designed to be used with both, small or large coils. Large coils offer extreme depth capabilities for big metal objects because of the strong and deep going magnetic field produced. Small coils are preferably used while searching for small objects like single coins or gold nuggets.

[Carl-NC]

Do you mean this coil?

[HAPPY]

yeah，that's right！ How it works without interference？If DIY，what shall we do？

[Carl-NC]

The lower coil is a normal PI coil... it transmits and receives as usual. The upper coil is a receive-only, and connected out-of-phase with the lower coil. An RX target signal is stronger on the lower coil and weaker on the upper coil so when they subtract you lose a little bit of depth. Far-field EMI is about the same on both coils so it subtracts to near-zero.

[6666]

The lower coil is a normal PI coil... it transmits and receives as usual. The upper coil is a receive-only, and connected out-of-phase with the lower coil. An RX target signal is stronger on the lower coil and weaker on the upper coil so when they subtract you lose a little bit of depth. Far-field EMI is about the same on both coils so it subtracts to near-zero.

Where there any published projects that used that coil ?

[6666]

Was Aziz's "top hat" coil like that ?

[HAPPY]

Sorry，I still have some trouble problems,for example,DIY the coils in Baracuda PI, the lower coil connect pcb，The upper coil…Could you show me in pictures or videos？

[Carl-NC]

Was Aziz's "top hat" coil like that ?

Yes, same principle as the top hat. I think the top hat had a large TX coil, small RX coil coplanar with the TX, then a reverse-RX coil elevated above.

[waltr]

How about this:
https://www.geotech1.com/cgi-bin/pag...rbyn/index.dat

[6666]

From Fat Bob.

[6666]

I think this was Aziz's top hat coil, or some variation of it
shows how to connect it. search "top hat" in forum.

[HAPPY]

OK，thanks for your answers , I will try.If anyone have more info，welcome！

Regards